1. Field of Invention
The invention relates to a heat-dissipating structure and, in particular, to a heat-dissipating structure for the expansion board architecture.
2. Related Art
Technological advances enable electronic devices to have better functions and efficiencies. However, they all generate heat during their operations. If such heat cannot be appropriately dissipated, their efficiencies generally reduce. More seriously, the electronic devices may be burned. Therefore, heat-dissipating devices have become an indispensable part of modern electronic devices.
Conventional heat-dissipating devices are designed for specific heat-generating elements. For those with lower working frequencies, the heat generated by them can be controlled to an extent that only heat-dissipating fins are sufficient. FIG. 1 is a side view of the conventional heat-dissipating device. As shown in the drawing, there are many heat-dissipating fins 13 with a high coefficient of thermal conduction tightly attached to the heat-dissipating elements 12 on the printed circuit board (PCB) 11. This increases the contact area between the heat-generating elements and air. Through natural convection, the heat-dissipating fins 13 with a high coefficient of thermal conduction dissipate heat produced by the heat-generating elements 12 into cold air.
However, many electronic products nowadays are designed to be more compact, have more functions, and run at higher frequencies. In particular, the industrial computer is more compact in size than office or home computers due to its working environment.
Therefore, the above-mentioned heat-dissipating device has to be improved in order to satisfy the above-mentioned requirements. FIG. 2 is a three-dimensional view of the heat-dissipating device for the industrial computer in the prior art. FIG. 3 is a three-dimensional exploded view of the heat-dissipating device in FIG. 2.
The industrial computer 20 includes a heat-dissipating housing 21, a heat-conducting block 22, and a motherboard 23. The heat-dissipating housing 21 is the aluminum extrusion type. Its outer surface is extended outwards into a plurality of heat-dissipating fins 231 in the horizontal or vertical direction. The purpose is to increase the contact area between the heat-dissipating housing 21 and the ambient air. The front and back of the heat-dissipating housing 21 can be fixed onto a front cover 212 and a back cover 213 through a fixing element 211. The inner side of the heat-dissipating housing 21 is in touch with the heat-dissipating block 22. The other end of the heat-dissipating block 22 is in touch with the heat-dissipating element 24 on the motherboard 23. The shape of the heat-dissipating block 22 can be the same as several electronic elements whose heat needs to be dissipated.
When the heat-dissipating elements 24 operate and generate heat, the heat is transferred by the heat-dissipating block 22 to the heat-dissipating housing 21. Through natural convection, the heat-dissipating fins 231 on the surface of the heat-dissipating housing 21 dissipate the heat of the heat-generating elements 24 into air.
For the heat-dissipating structure in the prior art, the heat-dissipating housing 21, the heat-dissipating block 22, and the motherboard 23 have to be fixed, respectively. Each fixing renders an assembly tolerance. The more assembly steps there are, the larger the accumulated assembly tolerance becomes. In the prior art, there are four tolerances in the assembly. The resulting total tolerance will affect the connections between elements. This generally leads to a lower heat-dissipating efficiency in industrial computers.
Moreover, this kind of heat-dissipating devices dissipates heat with the heat-dissipating block 22 attached on the heat-generating elements 24. To achieve the expected efficiency, the heat-dissipating block 22 has to occupy a certain space. Therefore, they may not be suitable for all industrial computers, particularly those using the expansion board architecture. Such industrial computers can expand their functions by inserting expansion boards at any time according to user's need.
For industrial computers using this expansion board architecture, there is a limited space between the motherboard and the expansion board. In the prior art, some space is required in order for the heat-dissipating structure to touch the heat-generating elements. This is not suitable for the expansion board architecture. If the heat-generating elements are right between the motherboard and the expansion board, the heat generated by the heat-generating elements cannot be effectively dissipated using the existing heat-dissipating devices. It is therefore necessary to provide a new heat-dissipating structure. In addition to satisfying the limit in space, it has to be able to effectively dissipate the heat generated by the heat-generating elements on the motherboard or the expansion board.
In summary, the prior art has had the problem that the heat-dissipating structure occupies larger space and cannot be conveniently used in the expansion board architecture to remove heat produced by the heat-generating elements between the motherboard and the expansion board. Moreover, it is likely to have an assembly tolerance. Consequently, it is imperative to solve these problems using improved techniques.